From the screens it looks like you've got pretty far with the design. Good work And a little tip for the graphics : You could add some variance in the trees (size + skin , maby even shape) and you should make a new GUI(interface). If you cant make a better one,ask in User Requests I'm shure someone will help you. Its not hard if you know what you're doing...

PS.: Keep working on it Not everyone manages to get half of it done,not to mention something playable.